Caterpillar 189-1720 Analog Gauge Tester Group{0785} Caterpillar

Introduction

The 189-1720 Analog Gauge Tester Group allows the user to test an entire analog gauge system and quickly determine the root cause of a failure on Caterpillar machines. The different analog gauges that can be tested are temperature, fuel, pressure, and articulation.

NOTE: The 189-1720 Analog Gauge Tester is NOT for use with the Caterpillar Quad Gauge.

Illustration 1. 189-1720 Gauge Analog Tester Group.

(1) Analog Gauge Tester.

(2) 6V-4094 Foam Liner (installed inside of 6V-3073 Case).

(3) NEEG2990 Decal (applied to 6V-3073 Case).

(4) 6V-3073 Case.Not Shown: NEHS0786 Tool Operating Manual.

Illustration 2. The 189-1720 Analog Gauge Tester.

(1) Dial 1 is a 0 to 50 Ohm Resistance Range.

(2) Dial 2 is a 0 to 500 Ohm Resistance Range.

(3) Dial 3 is a 0 to 1500 Ohm Resistance Range.

(4) Dial 4 is a 0 to 34,000 Ohm Resistance Range.

(5) Fuse Cap.

Benefits of Using the Analog Gauge Tester

* Decreases troubleshooting time.

* Reduces replacing good components.

* Diagnose gauge system problems to determine if sensor, wiring, or gauge is faulty.

* Use with analog temperature, fuel, pressure, or articulation gauges.

* Easy to use, hand-held diagnostic tool.

Principle of Operation

The 189-1720 Analog Gauge Tester consists of four variable resistors, connected in series, and each variable resistor provides a different resistance range.

Illustration 3. Operational Schematic Of Analog Gauge Tester.

The output of the 189-1720 Analog Gauge Tester will be the combination of all four dials. Turning all dials counterclockwise to the "0" setting will make the resistance very low (<2 ohms). Turning a dial clockwise increases the resistance across the two clips of the Analog Gauge Tester to the value indicated by the pointer (white dot) on the dial.

The 189-1720 Analog Gauge Tester outputs a resistance, which can be used to simulate a sender's output. By connecting the Analog Gauge Tester in place of the sender in the "sender/gauge" electrical circuit, a good sender can be simulated, which allows the rest of the system to be checked. If the instrument panel's gauge does not properly respond when the Analog Gauge Tester is connected in place of the sender, move up the circuit towards the instrument panel's gauge to find the fault. The Analog Gauge Tester can also be connected at the instrument panel's gauge to test only the gauge's function.

Specifications

Using the 189-1720 Analog Gauge Tester

NOTE: The 189-1720 Analog Gauge Tester is NOT for use with the Caterpillar Quad Gauge.

1. Use the appropriate service information (schematic, wiring diagrams, etc.) to locate the sender, wiring, and instrument gauge.

2. Identify the gauge type (temperature, pressure, fuel, or articulation) and the Caterpillar part number. The gauge is located in the instrument panel and the part number is usually located on the gauge face.

3. Find the part number of the gauge in the specific look-up table (temperature, for example) in the "Gauge Look-Up Tables" section of this manual.

4. Find the gauge chart number next to the part number and refer to this chart in the "Gauge Charts" section of the manual. Each gauge type has a separate set of charts. All temperature charts are together, followed by pressure charts, fuel charts, and articulation charts.

NOTE: The Supply VDC (12 or 24) can be found next to the gauge chart number. This is the Voltage needed from an external power supply to test the gauge if it is removed from the instrument panel.

5. Turn all four dials of the 189-1720 Analog Gauge Tester completely counterclockwise.

6. Set the dial(s) on the gauge tester to the number specified in the Resistance (Ohms) column for Check Point A in the Gauge Chart (see the "Setting Resistance Ohms" section for additional information on setting the dials).

7. Connect two clips (red and black) to the gauge/sender electrical circuit or directly to the gauge itself.

NOTE: Make sure the sender is electrically disconnected from the instrument gauge.

8. Turn the "Start" switch on the machine to the ON position to apply power to the gauge. If the gauge is disconnected from the electrical system, an external power supply will be required.

9. Read the instrument gauge and compare the actual reading to the typical, minimum, and maximum values in the Gauge Chart.

10. Turn the "Start" switch on the machine to the OFF position.

11. Repeat Steps 5 through 10 for all other Check Points (B, etc.) shown in the Gauge Chart.

Setting Resistance (Ohms)

1. Make sure each dial (1, 2, 3, and 4) is turned completely counterclockwise (zero).

NOTE: Do not try to guess the resistance value between preset marks on the front decal.

2. Turn the dials to the desired resistance setting. Using the lowest possible setting on each dial will increase the accuracy of the readings obtained during the test.

Examples of selecting the desired resistance by using dials with lowest resistance:

* For 200 Ohms:Set "Dial 2" (0 to 500) to 200.Do not set "Dial 3" (0 to 1500) to 200.

* For 1170 OhmsSet "Dial 3" (0 to 1500) to 1100.Set "Dial 2" (0 to 500) to 50.Set "Dial 1" (0 to 50) to 20.

Gauge Look-Up Tables

Temperature Gauges

1 Caterpillar part number on gauge face.

2 No Caterpillar part number on gauge face.

Pressure Gauges

Fuel Gauges

Articulation Gauges

Gauge Charts

Illustration 4. Pressure Gauge Dial Faces.

Temperature Gauge Charts

Note: Refer to Figure 5 in Illustration 4.

Note: Refer to Figure 6 in Illustration 4.

Note: Refer to Figure 2 in Illustration 4.

Note: Refer to Figure 7 in Illustration 4.

Note: Refer to Figure 7 in Illustration 4.

Note: Refer to Figure 7 in Illustration 4.

Note: Refer to Figure 1 in Illustration 4.

Note: Refer to Figure 3 in Illustration 4.

Note: Refer to Figure 4 in Illustration 4.

Note: Refer to Figure 9 in Illustration 4.

Pressure Gauge Charts

Fuel Gauge Charts

Articulation Gauge Chart

Maintenance

Check and Calibrate the Analog Gauge Tester

The 189-1720 Analog Gauge Tester is calibrated at the factory, but may occasionally need to be recalibrated using a Digital Multimeter.

1. Connect a Digital Multimeter to the two clips of the gauge tester.

2. Turn the four dials all the way to the counterclockwise position.

3. Use Chart A below to determine if each of the variable resistors are calibrated correctly. Turn "Dial 1" to the 25 Ohms setting and read the Digital Multimeter. The reading should be a minimum of 22.5 Ohms and a maximum of 27.5 Ohms (± 10% of the Calibration Point). For the most accurate test results, the Digital Multimeter's reading should be as close to 25 Ohms as possible.

4. To recalibrate "Dial 1":

a. Turn "Dial 1" until a 25 Ohm reading is shown on the Digital Multimeter.

b. Loosen the set screw on the dial using 9S-1742 Hex Key Wrench.

c. Carefully turn the dial so the pointer (white dot) lines up with the 25 Ohm mark. Make sure the variable resistor's steel shaft does not move when the dial is turned.

d. Tighten the set screw in the dial.

5. Verify the calibration. Turn the dial completely counterclockwise and then back to the 25 Ohm mark. Recheck the reading on the digital multimeter and make sure it is within the specification range in Chart A.

6. If necessary, repeat Steps 4 and 5. Continue this procedure for Dials 2, 3, and 4.

Fuse Test/Replacement

If the Analog Gauge Tester is not operating, use a Digital Multimeter to check the output. Move the dials and if the output's resistance remains at 0 Ohms, then the fuse should be checked.

1. To remove the fuse, turn fuse cap (5) to the left one-half turn and pull the fuse free.

2. Use a Digital Multimeter to test the fuse.

a. Set the Digital Multimeter on the 200 Ohm scale to check the continuity between the two legs of the fuse.

b. If the fuse is good (reusable) the resistance will be less than 1 Ohm.

c. A defective fuse will measure infinite Ohms (OL on the Digital Multimeter's display) and should be replaced.

d. If the fuse is defective, install a 3AG, 5 AMP, Fast Blow Fuse as a replacement.

Service

If the 189-1720 Analog Gauge Tester does not operate properly, then recalibrate it using the procedure in the "Calibrating the Analog Gauge Tester" section. If it continues to not operate properly, then contact the Caterpillar Service Technology Group (CSTG) for information on how to obtain the needed repair service.

CSTG provides the instrument's user with a warranty of one year from purchase date. If the reason for failure is determined to be abuse, the warranty is declared void. Any out-of-warranty repairs will be charged to the owner.

For any product support questions with your instrument, contact your Caterpillar contact or CSTG at:

If the instrument, or any part of it needs repair, then contact and send it to:

For information on service tools or shop supplies contact Caterpillar Service Technology Group on:

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